Advances in molecular biology for extremophiles have long held promise to provide a broad range of stable enzymes and novel biochemistry for industrial and bioenergy applications. Recombinant expression of hyperthermophilic proteins in Escherichia coli has had many successes but also proven limiting (1). Often recombinant proteins expressed in non-native organisms lack appropriate post translational modifications, binding partners, and/or fail to fold correctly, all of which can result in inactive enzymes. Broadly applicable recombinant DNA technologies for archaea have been slow to develop in part due to the highly diverse biology and environments of this domain of life (2). Many Sulfolobus vectors have been developed but only narrowly applied due to a number of technical challenges (reviewed in (3)). Recent advances with archaeal genetics in Pyrococcus, Sulfolobus and other extremophiles have reinvigorated interest in the promise of extremophilic enzymes for industrial application (4-11).
The hyperthermophilic/acidophilic microbe Sulfolobus solfataricus that thrives at 80° C. and a pH of 2-3 in volcanic springs across the globe and is among the most well studied archaeal hyperthermophiles (12). Many natural viral pathogens of Sulfolobus have been used for a number of years to advance the development of viral shuttle vectors for this extremophile (11, 13-16). However, the large sizes of these vectors (˜20 kb), among other technical difficulties, have made rapid and efficient cloning impractical to date (17).